This file is indexed.

/usr/include/cxxtools/singleton.h is in libcxxtools-dev 2.2.1-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/*
 * Copyright (C) 2005-2006 by Marc Boris Duerner
 * Copyright (C)      2006 by Aloysius Indrayanto
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef cxxtools_Singleton_h
#define cxxtools_Singleton_h

#include <cxxtools/noncopyable.h>

#include <memory>
#include <cstdlib>

namespace cxxtools {

    /** @brief Singleton class template
       @ingroup cxxtools

        @param T Type of the singleton
        @param A Allocator for type T

        The Singleton class template can be used to easily implement the Singleton
        design pattern. It can either be used directly or as a base class. An
        allocator can be used to control how the singleton instance will be
        allocated.

        The follwing example shows how to use the singleton as a base class:
        @code
              class MySingleton : public Singleton<MySingleton>
              {
                   friend class Singleton<MySingleton>;

                   // ...
               };
        @endcode
     */
    template <typename T, typename A = std::allocator<T> >
    class Singleton : private NonCopyable
    {
        public:
            typedef A Allocator;

        public:
            /** @brief Returns the instance of the singleton type

                    When called for the first time, the singleton instance will be
                    created with the specified alloctaor. All subsequent calls wikk
                    return a reference to the previously created instance.

                @return The singleton instance
             */
            static T& instance()
            {
                if(!_instance)
                {
                    try
                    {
                        _instance = (T*)_allocator.allocate(1);
                        new (_instance) T();
                        std::atexit(&atExit);
                    }
                    catch( const std::bad_alloc& e )
                    {
                        throw e;
                    }
                    catch(...)
                    {
                        _allocator.deallocate(_instance, 1);
                        _instance = 0;
                        throw;
                    }
                }

                return *_instance;
            }

        protected:
            /**  @brief Constructor
             */
            Singleton()
            { }

            /**  @brief Destructor
             */
            ~Singleton()
            { }

        private:
            /** @brief Exit handler

                This function is set as the program exit handler and will destroy
                the singleton instance at the end of the program using the
                specified allocator.
             */
            static void atExit()
            {
                _instance->~T();
                _allocator.deallocate(_instance, 1);
                _instance = 0;
            }

        private:
            static A  _allocator;
            static T* _instance;
    };


    template <typename T, typename A>
    A Singleton<T, A>::_allocator;


    template <typename T, typename A>
    T* Singleton<T, A>::_instance = 0;

} // namespace cxxtools

#endif